Roofcovering material

Abstract: Roofcovering material, consisting of a base layer (1), onto which, under insertion of a separating layer (2), a bituminous covering layer (3) is applied, wherein in the base layer is formed by a supporting layer, by means of which the roofcovering material may be mechanically fastened to a foundation, such as a roof construction, and wherein the seperating layer is provided with apertures, through which the covering layer is firmly adhered to the supporting layer.

Description: The invention relates to a roofcovering material, formed by a base layer, onto which base layer, under insertion of a separating layer, a bituminous covering layer has been applied. From EP-A-0 251 374 is known a roofcovering material, formed by a base layer, onto which base layer, under insertion of a separating layer, a bituminous covering layer has been applied. The base layer is formed of non-woven glass fibers and is provided with apertures distributed over its surface through which molten bitumen may pass to fasten the roofcovering material to the roof. The separating layer is provided with perforations through which a limited bond exists between the covering layer and the base layer which is intended to easily break when the roofcovering material is exposed to stress as a result of the formation of cracks or fissures in the roof. The known roofcovering material as described above has the drawback, that this has to be applied to a roof construction by heating the bitumen with an open flame, which constitutes an important fire hazard. It is not possible to apply the roofcovering material mechanically to the roof, for instance by means of a screw with washer plates or -strips, without the roofcovering material to come to lie completely loose when exposed to wind load. The base layer comprised of the glass fibres tissue tears easily, so that, when the roofcovering material is exposed to windload, the base layer will break down, and thereby the connection between the covering layer, the base layer and the screwed connection will be broken, resulting in the roofcovering material to come to lie loose on the roof. The invention aims to obviate these drawbacks of the known roofcovering material. The roofcovering material according to the invention to that end is characterized, in that the base layer is formed by a supporting layer, by means of which the roofcovering material may be mechanically fastened to a foundation, such as a roof construction, and wherein the separating layer is provided with apertures, through which the covering layer is firmly adhered to the supporting layer, while the separating layer is applied loosely or in spaced relationship over the supporting layer or the covering layer, such, that the covering layer and the supporting layer, outside of the area of the apertures, are movable with respect to each other, while the separating layer and the supporting layer are compressible or foldable under an elastic deformation of the covering layer. According to a characteristic of the roofcovering material according to the invention, the supporting layer is provided with a reinforcement net. According to another characteristic of the roofcovering material according to the invention, the supporting layer is formed by a woven material or fabric or fabric mat, for instance a woven glass mat or glass fabric mat, or is formed by a foil or film, such as for instance a metal foil or plastic film, or by a fleece, for instance a polyester fleece or film, or by paper, or by a linked or unlinked gauze, or a scrim. Further the supporting layer may be made up of glass fibres, carbon fibres, plastic fibres, textile or fabric fibres, metal threads, or mixtures thereof, and which may be impregnated by a binding agent, be it fire-resistant or not. With an efficient embodiment of the roofcovering material according to the invention, the supporting layer is formed by glass fabric or glass fabric mat, or a woven glass mat. With the roofcovering material according to the invention, it is possible to fasten the roofcovering material mechanically to a roof construction by means of screws with washer plates or -strips. According to a characteristic of the roofcovering material according to the invention the separating layer is liquid or vapour tight, or in any case liquid or vapour tight during the manufacturing process of the roofcovering material, and preferably the separating layer is formed by a plastic film. Further, the separating layer may also be provided with a reinforcement net. The separating layer is applied loosely or in spaced relationship over the supporting layer or the covering layer, such, that the covering layer and the supporting layer, outside of the area of the apertures in the separating layer, through which the junctions between the covering layer and the supporting layer are formed, lie loose in relation to one another and are movable in relation to one another. With this measure it is achieved, that when the bituminous covering layer is cooled down, for instance during the manufacturing process of the roofcovering material, and/or at a later time, and shrinks, the bituminous covering layer is allowed to move (slide or glide) relative to the supporting layer. According to a further characteristic of the roofcovering material according to the invention the separating layer may be formed by a number of strips, which strips, according to a further characteristic, extend substantially square lenghtwise of the roofcovering material. According to another characteristic of the roofcovering material according to the invention the surface size of the supporting layer is larger than the surface size of the bituminous covering layer, such, that when the roofcovering material is unrolled and in a flat condition, the supporting layer, outside of the area of the junctions of the supporting layer and the covering layer, lies to a certain extent creased or folded relative to the covering layer. When the roofcovering material is applied to a roof in which fissures or cracks may be formed, or onto a roof which expands under the influence of heat and/or vapour, the covering layer, due to the larger size of the supporting layer with respect to the covering layer, is allowed to move together with the underlying roof construction and to undergo to a certain degree an elastic deformation. Further, when the sheet of roofcovering material is unrolled and applied onto a roof, the bituminius covering layer tends to shrink. In a favourable way, the separating layer is formed by a plastic film, of such a slight thickness, that when this film is adhered to the covering layer and is in spaced relationship to the supporting layer, this supporting layer may easily be compressed or undergo a slight creasing during the shrinking movement of the covering layer. According to a further characteristic of the roof covering material according to the invention, the apertures distributed over the separating layer, and accordingly the junctions between the supporting layer and the covering layer, are distributed over the surface of the seperating layer at equal distances from one another. The apertures distributed over the seperating layer, and accordingly the junctions, may cover between 2% and 90% of the surface of the seperating layer, more in particular 20% . Further, the apertures may have a size varying from 0,1 cm2 to 500 cm2, more in particular 4 cm2. The invention will now be described with reference to the accompanying drawing of an embodiment of an example. The figures 1 and 2 show a sectional view of the roofcovering material, wherein in figure 2 the connection between two sheets of roofcovering material is shown. With the roofcovering material as it is shown in the drawing, the sheet of roofcovering material is formed by a supporting layer 1 of glass fabric or glass fabric mat. Over the supporting layer 1 a seperating layer 2, in this example a flexible thin plastic film 2, is applied, which separates the supporting layer 1 from the bituminous covering layer 3, which is applied over the film 2, this however with the exceptions of the apertures 4 in the film 2, through which the material of the covering layer 3 has come into contact with the supporting layer 1 and where it has adhered itself firmly to the supporting layer 1, to form a permanent and firm junction between the supporting layer 1 and the covering layer 3. The plastic film 2 is applied loosely or in spaced relationship over the supporting layer 1, such, that the covering layer 3, outside of the area of the apertures tures 4, is movable with respect to the supporting layer 1. When the roofcovering material is cooled down, for instance during the manufacturing process thereof by means of hot bitumen, or at a later time, it will tend to shrink. When the roofcovering material is applied to the roof, and is unrolled, the bituminous covering layer 3 will shrink further. The surface size of the supporting layer 1 is larger than the surface size of the bituminous covering layer 3, such, that when the roofcovering material is unrolled and in a flat condition, the supporting layer 1, outside of the area of the junctions 4 of the supporting layer 1 and the covering layer 3, lies to a certain extent creased 5 or folded 5 relative to the covering layer 3. By means of the separating layer 2, which may easily be compressed or creased under the compression forces of the shrinking covering layer 3, it is thereby prevented, that the overlying bitumen layer follows this crease or fold formation of the supporting layer. With the roofcovering material according to the invention it is thereby possible to allow the bituminous covering layer to undergo an elastic deformation, such as a shrinking movement, whereby the underlying supporting layer, such as a flexible glass fabric mat or flexible woven fabric mat, is allowed to crease and fold, which creasing or folding may take place independantly from the covering layer, due to the presence of the separating layer. The roofcovering material may further be provided with a layer of granules 6, as shown in figure 1. With the roofcovering material according to the invention it is possible to apply a sheet of roofcovering material to a roof construction without the necessity of the use of an open flame. The sheet of roofcovering material is unrolled over the roof, whereby the edge 7 of the roofcovering material is fastened to the roof construction by means of screws 8 and washer plates or -strips. Near the edges 7 and 10 of the roofcovering material the supporting layer 1 overlaps the seperating layer 2, such that at the spot of the overlap 11 a direct connection is formed between the supporting layer 1 and the covering layer 3, so that the supporting layer 1 and the covering layer 3 at that place are firmly connected to each other. At the edge 10 the covering layer 3 overlaps the supporting layer 1 and the seperating layer 2, such, that the roofcovering material at the place of the overlap 12 is formed only by the covering layer 3. As can be seen in figure 2, the connection 9 between two sheets of roofcovering material placed side by side may be sealed by means of hot air, whereby the supporting layer 1 in the connection zone 9 has to be sealed to the underlying sheet, so that at wind load no notch effect or stress concentration appears at the transition where the supporting layer terminates, and where by means of bitumen of the underlying covering layer 3 a firm connection exists between the supporting layers of the two sheets. With another embodiment of the roofcovering material according to the invention, the supporting layer 1 may be formed by a film or polyester fleece 1. The supporting layer 1 may thereby, at or near the edge 10 of the roofcovering material, at the side turned away from the covering layer, be provided with a heat or fire resistant layer or -strip , which is not shown in the drawing. With this measure it is prevented, that near the formation of the overlap the supporting layer at the place over the overlap is melted away by the hot air. The supporting layer may also be provided with this heat or fire resistant layer at the side facing the covering layer, whereby this has the function of improving the fire safety of the roofcovering material.

Claims: Roofcovering material, consisting of a base layer [1], onto which, under insertion of a separating layer [2], a bituminous covering layer [3] is applied, characterized in that the base layer [1] is formed by a supporting layer [1] by means of which the roofcovering material may be mechanically fastened to a foundation, such as a roof construction, and wherein the separating layer [2] is provided with apertures [4], through which the covering layer [3] is firmly adhered to the supporting layer [1], while the separating layer [2] is applied loosely or in spaced relationship over the supporting layer [1] or the covering layer [3], such, that the covering layer [3] and the supporting layer [1], outside of the area of the apertures [4], are movable with respect to each other, while the separating layer [2] and the supporting layer [1] are compressible or foldable under an elastic deformation of the covering layer [3]. Roofcovering material according to claim 1, characterized in that the supporting layer [1] is provided with a reinforcement net. Roofcovering material according to claim 1 or 2, characterized in that the supporting layer [1] is formed by a woven material, such as a fabric or a fabric mat, or is formed by a scrim, or a foil or film, such as for instance a metal foil or plastic film, by a fleece, by paper, or by a linked or unlinked gauze. Roofcovering material according to claim 1, 2 or 3, characterized in that the supporting layer [1] is made up of glass fibres, carbon fibres, plastic fibres, textile or fabric fibres, metal threads, paper fibres, or mixtures thereof. Roofcovering material according to claim 1 or 2, characterized in that the supporting layer [1] is formed by a glass fabric or glass fabric mat. Roofcovering material according to claim 1 or 2, characterized in that the supporting layer [1] is formed by a polyester film, tissue or web. Roofcovering material according to one of the preceding claims, characterized in that the supporting layer [1], at one or both of its sides, completely or only along one or both edges of the roofcovering material, is provided with a heat or fire protective layer. Roofcovering material according to one of the preceding claims, characterized in that the separating layer [2] is liquid or vapour tight, such as to prevent the covering layer [3] from adhering itself to the supporting layer [1], outside the area of the apertures in the separating layer [1]. Roofcovering material according to one of the preceding claims, characterized in that the separating layer [2] is provided with a reinforcement net. Roofcovering material according to one of the preceding claims, characterized in that the separating layer [2] is formed by a foil or film, such as for instance a metal foil or plastic film [2], and preferably is formed by a plastic film, or by a separating paste or a separating liquid. Roofcovering material according to one of the preceding claims, characterized in that the supporting layer [1] is formed by a number of strips. Roofcovering material according to claim 11, characterized in that the strips extend substantially square lenghtwise of the roofcovering material. Roofcovering material according to claim 11 or 12, characterized in that the strips have a width varying from 2 to 500 mm, preferably 50 mm. Roofcovering material according to claim 11, 12 or 13, characterized in that the strips are positioned at a distance from one another, the distance varying from 0,1 to 500 mm, preferably 10 mm. Roofcovering material according to one of the preceding claims, characterized in that the surface size of the supporting layer [1] is larger than the surface size of the bituminous covering layer [3], such, that when the roofcovering material is unrolled and in a flat condition, the supporting layer [1], outside of the area of the junctions [4] of the supporting layer [1] and the covering layer [3], lies to a certain extent creased [5] or folded [5] relative to the covering layer [3]. Roofcovering material according to one of the preceding claims, characterized in that the apertures [4] distributed over the separating layer [1], and accordingly the junctions [4] between the supporting layer [1] and the covering layer [3], are distributed over the surface of the separating layer [2] at equal distances from one another. Roofcovering material according to one of the preceding claims, characterized in that the apertures [4] distributed over the separating layer [2], and accordingly the junctions [4], cover between 2% and 90% of the surface of the separating layer [2]. Roofcovering material according to claim 17, characterized in that the apertures [4] distributed over the separating layer [2] cover 20% of the surface of the separating layer [2]. Roofcovering material according to one of the preceding claims, characterized in that the apertures [4] have a size varying from 0,1 cm2 to 500 cm2, more in particular 4 cm2. Roofcovering material according to one of the preceding claims, characterized in that the apertures [4] distributed over the separating layer [2] have a round shape. Roofcovering material according to one of the preceding claims, characterized in that near or at the edges [7, 10] the supporting layer [1] overlaps the separating layer [2], such that at the place of the overlap [11] a direct bond between the supporting layer [1] and the covering layer [3] exists, such that the supporting layer [1] and the covering layer [3] are at that place firmly connected. Roofcovering material according to claim 21, characterized in that the overlap [12] has a width varying from 0,1 to 200 mm, preferably 10 mm. Roofcovering material according to one of the preceding claims, characterized in that at or near at least one of the edges [10] the covering layer [3] overlaps the supporting layer [1] and the separating layer [1], such, that the roofcovering material at the place of the overlap [12] is formed solely by the covering layer [3]. Roofcovering material according to claim 23, characterized in that the overlap [12] of the covering layer [3] over the separating layer [2] and the supporting layer [1] has a width varying from 0,1 mm to 300 mm, preferably 30 mm.

Inventors: MUELBECK MARTIN, MUELBECK, MARTIN
Applicants: MODIGLASS MODIFIED ASPHALT, MODIGLASS MODIFIED ASPHALT-
Application year: 1994
Main classification: E04D5
IPC codes: B32B11, E04D5, B32B3